我们知道Java中有三种注释语句：1.//用于单行注释。

2./*...*/用于多行注释，从/*开始，到*/结束，不能嵌套。3./**...*/则是为支持jdk工具javadoc.exe而特有的注释语句。

javadoc工具能从java源文件中读取第三种注释，并能识别注释中用@标识的一些特殊变量(见表)，制作成Html格式的类说明文档。 javadoc不但能对一个java源文件生成注释文档，而且能对目录和包生成交叉链接的html格式的类说明文档，十分方便。

注释中可以出现的关键字，以@开头：

@author 作者名

@version 版本标识

@parameter 参数名及其意义

@since 最早出现的JDK版本

@return返回值

@throws异常类及抛出条件

@deprecated 引起不推荐使用的警告

@see 交叉参考

下面是javadoc.exe的用法

C:\java>javadoc -help

C:\java>javadoc -help

usage: javadoc [options] [packagenames] [sourcefiles] [classnames] [@files]-overview Read overview documentation from HTML file-public Show only publicclasses and members-protected Show protected/public classes and members (default)-package Show package/protected/publicclasses and members-privateShow all classes and members-help Display command line options and exit-doclet Generate output via alternate doclet-docletpath Specify where to find doclet classfiles-sourcepath Specify where to find source files-classpath Specify where to find user classfiles-exclude Specify a list of packages to exclude-subpackages Specify subpackages to recursively load-breakiterator Compute 1st sentence with BreakIterator-bootclasspath Override location of class files loaded by the bootstrap classloader-source Provide source compatibility with specified release-extdirs Override location of installed extensions-verbose Output messages about what Javadoc is doing-locale Locale to be used, e.g. en_US or en_US_WIN-encoding Source file encoding name-J Pass directly to the runtime system

Provided by Standard doclet:-d Destination directory foroutput files-use Create class and packageusage pages-version Include @version paragraphs-author Include @author paragraphs-docfilessubdirs Recursively copy doc-file subdirectories-splitindex Split index into one file per letter-windowtitle Browser window title forthe documenation-doctitle Include title forthe overview page-header Include header text foreach page-footer Include footer text foreach page-bottom Include bottom text foreach page-link Create links to javadoc output at

-linkoffline Link to docs at using package list at

-excludedocfilessubdir :.. Exclude any doc-files subdirectories with given name.-group :.. Group specified packages together in overviewpage-nocomment Supress description and tags, generate only declarations.-nodeprecated Do not include @deprecated information-noqualifier ::... Exclude the list of qualifiers from the output.-nosince Do not include @since information-nodeprecatedlist Do not generate deprecated list-notree Do not generate classhierarchy-noindex Do not generate index-nohelp Do not generate help link-nonavbar Do not generate navigation bar-quiet Do not display status messages to screen-serialwarn Generate warning about @serial tag-tag ::Specify single argument custom tags-taglet The fully qualified name of Taglet to register-tagletpath The path to Taglets-charset Charset for cross-platform viewing of generated documentation.-helpfile Include file that help link links to-linksource Generate source in HTML-stylesheetfile File to change style of the generated documentation-docencoding Output encoding name

C:\java>下面请看用javadoc生成的文档(请点击本页上面的观看演示链接)

生成文档：

C:\java>javadoc JavadocDemo.java

Loading source file JavadocDemo.java...

Constructing Javadoc information...

Standard Doclet version1.4.2_03

Generating constant-values.html...

Building treeforall the packages and classes...

Building indexforall the packages and classes...

Generating overview-tree.html...

Generating index-all.html...

Generating deprecated-list.html...

Building indexforall classes...

Generating allclasses-frame.html...

Generating allclasses-noframe.html...

Generating index.html...

Generating packages.html...

Generating JavadocDemo.html...

JavadocDemo.java:11: warning -Tag @see: reference not found: javax.swing.Japplet

Generating serialized-form.html...

Generatingpackage-list...

Generating help-doc.html...

Generating stylesheet.css...1warning

C:\java>附源文件：import java.applet.*;import java.awt.*;import java.awt.event.*;/***JavadocDemo.java,一个显示JavaDoc注释的Applet

*

注意这只是HelloApplet的一个带注释的版本

*@seejava.applet.Applet

*@seejavax.swing.Japplet*/

public class JavadocDemo extendsApplet{/**init()是一个Applet方法，由浏览器调用进行初始化

* 只调用一次

*@return无*/

public voidinit(){//创建并添加一个按钮//其它什么也不做

Button b;

b=new Button("Hello");

add(b);

show();

}/**paint() 是一个AWT组件方法，在组件要绘制时调用，只

* 是在Applet的窗口中画带色的方框。

* 参数 g一个java.awt.Graphics

* 用在所有绘制方法中*/

public voidpaint(Graphics g){int w=getSize().width,h=getSize().height;

g.setColor(Color.yellow);

g.fillRect(0,0,w/2,h);

g.setColor(Color.green);

g.fillRect(w/2,0,w,h);

g.setColor(Color.black);

g.drawString("Welcome to Java",50,50);

}/**show()用于使组件可见，此方法在

* JDK1.1中被归入不推荐使用

*@since1.0

*deprecated换用setVisible(true)*/

public voidshow(){//由于覆盖了show(),此applet 不能显示

}/**Applet必须有一个公共的无参数构造方法

*@throwsjava.lang.IllegalArgumentException*/

publicJavadocDemo(){if(new java.util.Date().getDay()==0){throw new IllegalArgumentException("Never on a Sunday");

}

}

}